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71.
This experiment was conducted to evaluate the effects of dietary pyridoxine on disease resistance, immune responses and intestinal microflora of fish. A total of 1050 Jian carp (11.71 ± 0.05 g) were randomly distributed into seven groups, feeding diets containing graded levels of pyridoxine (0.2, 1.7, 3.2, 5.0, 6.3, 8.6 and 12.4 mg kg?1 diet). After 80 days of feeding, a challenge trial was conducted by injection of Aeromonas hydrophila for 17 days. Results indicated that with increasing dietary pyridoxine concentration up to 5.0 mg kg?1 diet, survival rate after challenge with A.hydrophila and phagocytic activity of leukocyte were improved (P < 0.05), and plateaued thereafter (P > 0.05). Red blood cell and white blood cell counts were lowest when fed the diet containing 1.7 mg pyridoxine kg?1 diet. Haemagglutination titre, lysozyme activity, acid phosphatase activity, total iron‐binding capacity, antibody titre and immunoglobulin M content followed the similar pattern to that observed with survival rate. Aeromonas hydrophila, Escherichia coli and Lactobacillus counts in intestine were not affected by dietary pyridoxine concentration (P > 0.05). These results suggested that pyridoxine could enhance immune response of fish. 相似文献
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73.
Yi-juan HAN Zhen-hui ZHONG Lin-lin SONG Olsson Stefan Zong-hua WANG Guo-dong LU 《农业科学学报》2018,17(6):1252-1266
Jacalin-related lectins (JRLs) are widely distributed carbohydrate-binding proteins in the plant kingdom, which play key roles in development and pathogen defense. In this study, we profiled evolutionary trajectory of JRLs family in 30 plant species and identified domain diversification and recombination leading to different responsive patterns of JRLs in rice during defense against rice blast. All of 30 plant species analyzed in our study have two types of JRLs by containing either a single jacalin or repeated jacalin domains, while chimeric jacalins exist in more than half of the species, especially in the Poaceae family. Moreover, Poaceae species have evolved two types of unique chimeric JRLs by fusing the jacalin domain(s) with dirigent or NB_ARC domain, some of which positively regulate plant immunity. Seven Poaceae-specific JRLs are found in the rice genome. We further found expression of rice JRLs, including four Poaceae-specific JRLs, are induced by Magnaporthe oryzae infections at either early or late infection stages. Overall, the results present the evolutionary trajectory of JRLs in plant and highlight essential roles of Poaceae specific JRLs against pathogen attacks in rice. 相似文献
74.
Effects of dietary humic acid on growth performance,haemato‐immunological and physiological responses and resistance of Rainbow trout,Oncorhynchus mykiss to Yersinia ruckeri
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Sevdan Yılmaz Sebahattin Ergun Ekrem Şanver Çelik Murat Yigit 《Aquaculture Research》2018,49(10):3338-3349
This study investigated the effects of dietary humic acid sodium salt on growth performance, haemato‐immunological and physiological responses, and resistance of rainbow trout, Oncorhynchus mykiss to Yersinia ruckeri. The experimental fish were divided into four groups; three of them were fed with humic acid incorporated diets (0.3% H3, 0.6% H6, 1.2% H12) and an additive free basal diet served as the control. Growth performance and haematological parameters of rainbow trout were not affected by humic acid supplemented diets (p > 0.05). However, dietary humic acid especially with 0.6% incorporation significantly increased stomach pepsin, intestinal trypsin and lipase activities p < 0.05. Following 60 days of feeding trial, fish were challenged with Yersinia ruckeri for 20 days. At the end of the challenge period, significantly higher (p < 0.05) survival rates were found in the 6% humic acid group compared to all other experimental treatment. Thus humic acid might replace antibiotics in diets for rainbow trout to control yersiniosis. 相似文献
75.
采用盆栽方法研究不同浓度(2‰,4‰,6‰)中性复合盐对具有不同遗传背景的两种基因型菊芋幼苗(LZJ028有性繁殖能力强且营养品质高;LZJ017块茎产量高)生长和光合等生理特性的影响,探究不同遗传背景菊芋幼苗对盐胁迫的响应差异。结果表明:(1)当盐浓度为4‰和6‰时,两种基因型菊芋幼苗的株高、叶面积、冠幅和地上部分干物质和鲜物质积累(与对照相比)均下降,LZJ028基径、叶面积和地上部分干、鲜物质积累下降幅度(4.24%和6.26%,14.82%和29.67%,8.51%和19.68%,7.62%和22.38%)均显著低于LZJ017的降幅(9.78%和29.75%,58.33%和63.18%,15.77%和26.88%,40.62%和61.82%)。(2)随着盐浓度升高,两种基因型菊芋幼苗叶片的SOD活性、脯氨酸和可溶性糖含量均显著升高(如盐浓度为6‰时LZJ017和LZJ028的SOD活性比对照组升高了0.41倍和1.87倍;脯氨酸升高了8.26倍和42.92倍;可溶性糖含量升高了0.39倍和1.18倍),LZJ028的各指标升高幅度均较大。(3)盐浓度升高,两种基因型菊芋幼苗叶片净光合速率、蒸腾速率、气孔导度和叶绿素含量均降低,LZJ028净光合速率和气孔导度下降幅度均低于LZJ017;盐浓度升高,两种菊芋幼苗PSⅡ潜在活性和最大光化学效率也均下降,而初始荧光升高,如盐浓度为6‰时与对照相比LZJ028最大光化学效率和初始荧光变化幅度(10.53%和4.81%)低于LZJ017的变化幅度(43.04%和52.73%)。研究表明,盐胁迫主要抑制两种基因型菊芋叶片PSⅡ活性和碳水代谢速率进而抑制其生长,二者均通过提高保护酶SOD活性、增加渗透调节物质等策略缓解盐胁迫造成的伤害;LZJ028较耐盐,LZJ017对盐较敏感。 相似文献
76.
益蝽Picromerus lewisi Scott是一种重要的捕食性昆虫,为探究其控害潜能,在实验室条件下研究不同龄期的益蝽对粘虫的捕食能力。选择饥饿24 h的3、4、5龄益蝽若虫和成虫对不同密度的3龄粘虫进行捕食量测定试验,试验结果为3、4、5龄益蝽若虫和成虫的日平均捕食量分别为3.33、4.23、8.00和6.50头,每个龄期的捕食功能反应都符合HollingⅡ圆盘方程,其攻击率分别为1.036、0.742、1.445和1.422,处理猎物的时间分别为0.313、0.158、0.112和0.135 d;试验中发现益蝽偏食活猎物。结果表明利用益蝽进行生物防治时,选择5龄若虫,控害效果最好。 相似文献
77.
J.W. Hong S.H. Lee M. Moniruzzaman Y. Park S.H. Won H.Y. Jo S.S.O. Hung S.C. Bai 《Aquaculture Nutrition》2018,24(1):36-46
A feeding trial was conducted to evaluate the optimum dietary level of eicosapentaenoic acid (EPA, 20:5n‐3) based on growth and non‐specific immune responses in juvenile rock bream. A basal diet without EPA supplementation was used as a control, and six other diets were prepared by supplementing with 4, 8, 12, 16, 20 or 40 g of EPA per kg diet. The actual EPA concentrations of the diets were 0.5, 4.3, 8.5, 13.0, 16.8, 21.0 and 41.2 g of EPA per kg diet, and the diets were abbreviated as EPA0.5, EPA4.3, EPA8.5, EPA13.0, EPA16.8, EPA21.0 and EPA41.2, respectively. Triplicate groups of fish averaging 1.06 ± 0.01 g (mean ± SD) were fed one of the seven experimental diets at the apparent satiation for 8 weeks. At the end of the feeding trial, weight gain, specific growth rate and feed efficiency of fish fed EPA16.8, EPA21.0 and EPA41.2 diets were significantly higher than those of fish fed EPA0.5, EPA4.3, EPA8.5 and EPA13.0 diets (p < .05). Superoxide dismutase activity of fish fed EPA16.8, EPA21.0 and EPA41.2 diets were significantly higher than those of fish fed EPA0.5, EPA4.3 and EPA8.5 diets. Fish fed EPA21.0 and EPA41.2 diets showed significantly higher lysozyme activity than did fish fed EPA0.5, EPA4.3, EPA8.5 and EPA13.0 diets. The broken‐line analysis of weight gain indicated that the optimum dietary EPA level was 16.7 g/kg diet. These results suggested that the optimum dietary EPA level in juvenile rock bream could be greater than 16.7 g/kg diet but less than or equal to 16.8 g/kg diet based on the broken‐line analysis and the ANOVA test of weight gain. 相似文献
78.
为研究软母线刚度对特高压电气设备地震响应的影响,建立考虑刚度的软母线位形函数、最大弧垂及软母线最大应力的计算公式。通过软母线连接的特高压设备振动台模型试验与有限元计算的对比分析,验证了笔者给出的考虑刚度的软母线位形函数、最大弧垂计算公式的正确性。有限元分析结果表明:当软母线的刚度增大时,软母线的垂跨比减少,软母线与特高压设备之间的地震耦合作用增强,增强了软母线对设备的拉伸作用,从而使设备的地震反应随着导线刚度的增加而增加。软母线刚度对频率较高的设备其地震反应的影响要大于对设备频率较低设备地震反应的影响。 相似文献
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80.
通过对有关竞争情报与人际网络的期刊论文进行定性与定量分析。主要利用SATI3.2统计高频词汇、发文机构、期刊来源,并运用社会分析软件UCINET6.0将构建的高频关键词共现矩阵数据转换为一个网络图,以及对中心度和聚类的分析。从而进一步分析有关竞争情报与人际网络期刊论文的研究热点及发展动态。 相似文献